The Voyager 1 spacecraft is at the limit of the 'heliosheath', where particles streaming from the Sun clash with the gases of the galaxy. Contrary to scientists' expectation of a sharp, violent edge, the boundary seems to be a tepid place, where the solar wind mingles with extrasolar particles.
"We're in this mixed-up region where the Sun still has some influence," says Stamatios Krimigis, a physicist at the Applied Physics Laboratory of Johns Hopkins University in Laurel, Maryland. "It's certainly not what we thought."
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Instead, Krimigis says, measurements of low-energy charged particles show that the solar wind has gradually slowed to zero and is mingling with interstellar gases. Theories failed to predict this mixed-up environment, and Krimigis says it may even be possible that this is, in fact, what interstellar space looks like. "We may have crossed and don't know it, because nobody has a model that describes what we're seeing," he says.
34 years ago NASA launched Voyager 1 and it's not only still working, not only are we still learning things from it, it is at the edge of the solar system. We may have a human made space craft that has left the solar system in near future. Truly amazing.
